An integrated starter-generator (ISG) motor of a vehicle is directly integrated on a crankshaft of an engine. That is, in place of the conventional starter motor, a certain motor having a relatively large transient power is used directly to drive the vehicle in place of the engine in a short period at a starting stage, and meanwhile functions to start the engine to reduce the idle speed loss and pollution of the engine. During normal driving, the engine drives the vehicle, and the ISG motor is powered off or functions as a generator; during braking, the ISG motor can further have a regeneration function to recycle the braking energy to achieve the energy-saving effect. In short, this is an energy-saving, environmental friendly and low-cost solution which is intermediate between hybrid powered vehicles and conventional vehicles.
The ISG is directly integrated on the crankshaft of the engine. In consideration of environment protection and the strategy of the sustainable energy development, manufacturers all strive to research on and make use of the ISG technologies. The ISG involves the technologies such as motors, modern power electronics, digital signal processing and modern control, and combines together the starting and generating functions of conventional vehicles. Moreover, the ISG has prominent advantages such as rapid start/stop control, good performance in energy regeneration and recycling and enhanced power assistance, and is particularly advantageous in exhaust pollution reduction and saving fuel. Therefore, the ISG is internationally recognized as a goal to be necessarily achieved for engine components of conventional vehicles, the hybrid-powered vehicles and future electric vehicles.
As compared to the micro hybrid power system, the ISG system, in addition, is able to use the generator for start/stop control of the engine, which further absorbs a part of the energy during decelerating and braking; and during the process of driving, adjusting the output power of the engine between the driving requirement of the vehicle and the charging requirement of the generator so that the engine operates more within a high efficiency range to improve the overall efficiency.
Currently, there are mainly two kinds of structures for a rotor device of the ISG motor as follows.
(1) FIG. 1 is a schematic view illustrating a first type of rotor device structure of an ISG motor in the prior art. As shown in FIG. 1, the rotor device mainly consists of a shaft 101, a bearing 102, a rotor supporting frame 103, a bearing 104, and a clutch driving disc 105. The shaft 101, the rotor supporting frame 103 and the clutch driving disc 105 are fixed mechanically, and the entire rotor device is supported on a housing of the ISG motor by bearings.
(2) FIG. 2 is a schematic view illustrating a second type of the rotor device structure of the ISG motor in the prior art. As shown in FIG. 2, the rotor device mainly consists of a rotor supporting frame 201, a bearing 202, a bearing 203, and a clutch driving disc 204 which are fixed mechanically, and the entire rotor device is supported on a housing of the ISG motor by bearings.
FIG. 2 differs from FIG. 1 in that, the rotor supporting frame 201 in FIG. 2 is equivalent to both the shaft 101 and the rotor supporting frame 103 in FIG. 1.
As can be seen, the rotor devices of the conventional ISG motors all consist of multiple components which are fixed together mechanically (e.g., through bolt connection), and are all supported by means of at least one bearing. Consequently, the cumulative deviation of the system will be increased in the processing and manufacturing and the components assembling processes so that the entire system has poor stability and consistency.